Baffle For Damper With Electromechanical Valve

ABSTRACT

A shock absorber includes a pressure tube forming a working chamber. A reserve tube is concentric with and radially outward from the pressure tube. A baffle is positioned radially outward from the pressure tube. A reservoir chamber is formed between the reserve tube and the baffle. A piston is attached to a piston rod and slidably disposed within the pressure tube. A rod guide is attached to the pressure tube and supports the piston rod. An electromechanical valve is positioned within the rod guide. A plurality of non-linear passageways are disposed between the baffle and at least one of the pressure tube and the reserve tube for transporting fluid between the electromechanical valve and the reservoir chamber.

FIELD

The present disclosure relates generally to hydraulic dampers or shockabsorbers for use in a suspension system such as a suspension systemused for automotive vehicles. More particularly, the present disclosurerelates to a baffle for a damper including an electromechanical valve.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

In general, conventional shock absorbers produce damping forcecharacteristics based on a velocity of a piston rod that translatesrelative to a body of the shock absorber. The shock absorber includes avalve through which oil flows during movement of the piston rod. Apressure differential is generated within the shock absorber based onthe configuration and location of the valve. The working pressuresprovide a resistive or damping force between the piston rod and the bodyof the shock absorber to provide a desired damping force characteristicof a vehicle's suspension.

Electronically adjustable shock absorbers are also available. Theseshock absorbers produce damping force characteristics as well but thedamping force is adjustable over a damping force range. As such,electronically-adjustable shock absorbers may provide multiple dampingforce characteristic curves for the same piston rod velocity.

Both conventional and electronically-adjustable shock absorbers mayexhibit a lower magnitude of damping force than desired if aninsufficient oil fluid volume is present in the shock absorber reservoirchamber or if the fluid is aerated. Many shock absorbers are configuredas twin tube shock absorbers where the reservoir contains both a liquidoil fluid and a pressurized gas within the same chamber. The oil fluidlevel within the reservoir changes during shock absorber operation butthe shock absorber is configured to maintain a minimum oil level at alltimes. In certain shock absorbers, the physical position of the valvesrelative to the liquid level in the reservoir may induce a mixing of gasand liquid thereby aerating the liquid oil. A resultant lag of dampingforce occurs due to the compressibility of the gas within the liquid. Itis at least one object of the present disclosure to mitigate aeration ofthe liquid within the shock absorber to minimize a lag in providing atarget damping force.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

A shock absorber includes a pressure tube forming a working chamber. Areserve tube is concentric with and radially outward from the pressuretube. A baffle is positioned radially outward from the pressure tube. Areservoir chamber is formed between the reserve tube and the baffle. Apiston is attached to a piston rod and slidably disposed within thepressure tube. A rod guide is attached to the pressure tube and supportsthe piston rod. An electromechanical valve is positioned within the rodguide. The baffle and the pressure tube form a fluid passage between theelectromechanical valve and the reservoir chamber.

The present disclosure also describes a shock absorber including apiston assembly attached to a piston rod and slidably disposed within apressure tube. The piston assembly divides a working chamber into anupper working chamber and a lower working chamber. The piston assemblyincludes a first valve assembly controlling fluid flowing through afirst fluid passage that connects the upper working chamber with thelower working chamber. A reservoir tube is disposed around the pressuretube. A baffle is positioned radially outward from the pressure tube andat least partially defines a baffle channel between the pressure tubeand the baffle. The reservoir chamber is positioned between the baffleand the reserve tube. A second valve is positioned within the pressuretube for controlling fluid flow between one of the upper and lowerworking chambers and the reservoir chamber. A rod guide supports thepiston rod and is attached to an end of the pressure tube. A secondfluid passage extends from one of the upper and lower working chambersto the baffle channel. An electromechanical valve is positioned withinthe rod guide for controlling fluid flow through the second passage. Thebaffle channel fluidly connects the electromechanical valve and thereservoir.

The present disclosure also describes a shock absorber where a pluralityof passageways are disposed between the baffle and the pressure tube.The plurality of passageways are defined by grooves in the baffle and atleast one of an outer surface of the pressure tube and an inner surfaceof the reserve tube. At least one of the plurality of passageways isdisposed in fluid communication with the electromechanical valve and thereservoir for transporting fluid from the electromechanical valve to thereservoir chamber with minimal foaming.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is an illustration of an automobile having shock absorbers whichincorporate the valve design in accordance with the present disclosure;

FIG. 2 is a side view, partially in cross-section of a dual-tube shockabsorber from FIG. 1 which incorporates the valve design in accordancewith the present disclosure;

FIG. 3 is an enlarged side view, partially in cross-section of thepiston assembly from the shock absorber illustrated in FIG. 2;

FIG. 4 is an enlarged side view, partially in cross-section of the basevalve assembly from the shock absorber illustrated in FIG. 2;

FIG. 5 is an enlarged side view, partially in cross-section of theelectromechanical valve assembly from the shock absorber illustrated inFIG. 2;

FIG. 6 is an enlarged cross-sectional perspective view of theelectromechanical valve assembly illustrated in FIGS. 2 and 5;

FIG. 7 is an enlarged cross-sectional view of the dual-tube shockabsorber illustrating fluid pressures and flows during a compressionstroke;

FIG. 8 is an enlarged cross-sectional view of the dual-tube shockabsorber illustrating fluid pressures and flows during a rebound stroke;

FIG. 9 is a side view, partially in cross-section of another dual-tubeshock absorber constructed in accordance with the present disclosure;

FIG. 10 is a side perspective view of the baffle of the dual-tube shockabsorber illustrated in FIG. 9;

FIG. 11 is a top cross-sectional view of the baffle of the dual-tubeshock absorber illustrated in FIG. 10, which is taken along section lineA-A;

FIG. 12 is a side view, partially in cross-section of another dual-tubeshock absorber constructed in accordance with the present disclosure;

FIG. 13 is a side cross-sectional view of the baffle of the dual-tubeshock absorber illustrated in FIG. 12;

FIG. 14 is a side perspective view of the baffle of the dual-tube shockabsorber illustrated in FIG. 12;

FIG. 15 is a top cross-sectional view of the baffle of the dual-tubeshock absorber illustrated in FIG. 14, which is taken along section lineB-B;

FIG. 16 is a side view, partially in cross-section of another dual-tubeshock absorber constructed in accordance with the present disclosure;

FIG. 17 is a side cross-sectional view of the baffle of the dual-tubeshock absorber illustrated in FIG. 16;

FIG. 18 is a side perspective view of the baffle of the dual-tube shockabsorber illustrated in FIG. 16;

FIG. 19 is a top cross-sectional view of the baffle of the dual-tubeshock absorber illustrated in FIG. 18, which is taken along section lineC-C;

FIG. 20 is a side view, partially in cross-section of another dual-tubeshock absorber constructed in accordance with the present disclosure;

FIG. 21 is a side elevation view of the baffle of the dual-tube shockabsorber illustrated in FIG. 20;

FIG. 22 is a side perspective view of the baffle of the dual-tube shockabsorber illustrated in FIG. 20; and

FIG. 23 is a top cross-sectional view of the baffle of the dual-tubeshock absorber illustrated in FIG. 22, which is taken along section lineD-D.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings.

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses. There isshown in FIG. 1 a vehicle incorporating a suspension system having shockabsorbers, each of which incorporates a valve assembly in accordancewith the present invention, and which is designated generally by thereference numeral 10. Vehicle 10 includes a rear suspension 12, a frontsuspension 14 and a body 16.

Rear suspension 12 has a transversely extending rear axle assembly (notshown) adapted to operatively support a pair of rear wheels 18. The rearaxle is attached to the body 16 by means of a pair of shock absorbers 20and by a pair of springs 22. Similarly, front suspension 14 includes atransversely extending front axle assembly (not shown) to operativelysupport a pair of front wheels 24. The front axle assembly is attachedto the body 16 by means of a pair of shock absorbers 26 and by a pair ofsprings 28.

Shock absorbers 20 and 26 serve to dampen the relative motion of theunsprung portion (i.e., front and rear suspensions 12, 14) with respectto the sprung portion (i.e., body 16) of vehicle 10. While vehicle 10has been depicted as a passenger car having front and rear axleassemblies, shock absorbers 20 and 26 may be used with other types ofvehicles or in other types of applications including, but not limitedto, vehicles incorporating non-independent front and/or non-independentrear suspensions, vehicles incorporating independent front and/orindependent rear suspensions or other suspension systems known in theart. Further, the term “shock absorber” as used herein is meant to referto dampers in general and thus will include McPherson struts and otherdamper designs known in the art.

Referring now to FIG. 2, shock absorber 20 is shown in greater detail.While FIG. 2 illustrates only shock absorber 20, it is to be understoodthat shock absorber 26 also includes the valve assembly design describedbelow for shock absorber 20. Shock absorber 26 only differs from shockabsorber 20 in the manner in which it is adapted to be connected to thesprung and unsprung masses of vehicle 10. Shock absorber 20 comprises apressure tube 30, a piston assembly 32, a piston rod 34, a reserve tube36, a base valve assembly 38 and a baffle 40.

Pressure tube 30 defines a working chamber 42. Piston assembly 32 isslidably disposed within pressure tube 30 and divides working chamber 42into an upper working chamber 44 and a lower working chamber 46. A seal48 is disposed between piston assembly 32 and pressure tube 30 to permitsliding movement of piston assembly 32 with respect to pressure tube 30without generating undue frictional forces as well as sealing upperworking chamber 44 from lower working chamber 46. Piston rod 34 isattached to piston assembly 32 and extends through upper working chamber44 and through a rod guide assembly 50. A pressure tube adapter 51 isdisposed between the rod guide assembly 50 and the upper end of thepressure tube 30 such that the pressure tube adapter 51 closes the upperend of pressure tube 30. In one non-limiting example, the pressure tubeadapter 51 may be press-fit into the upper end of the pressure tube 30during assembly. A bumper stop 53 positioned adjacent to the pressuretube adapter 51 extends annularly about the piston rod 34. The bumperstop 53 prevents the piston assembly 32 from contacting the pressuretube adapter 51 on the rebound stroke. The end of piston rod 34 oppositeto piston assembly 32 is adapted to be secured to the sprung mass ofvehicle 10. Valving within piston assembly 32 controls the movement offluid between upper working chamber 44 and lower working chamber 46during movement of piston assembly 32 within pressure tube 30. Becausepiston rod 34 extends only through upper working chamber 44 and notlower working chamber 46, movement of piston assembly 32 with respect topressure tube 30 causes a difference in the amount of fluid displaced inupper working chamber 44 and the amount of fluid displaced in lowerworking chamber 46. The difference in the amount of fluid displaced isknown as the “rod volume” and it flows through base valve assembly 38.

Reserve tube 36 surrounds pressure tube 30 to define a fluid reservoirchamber 52 located between the pressure tube 30 and the reserve tube 36.The bottom end of reserve tube 36 is closed by a base cup 54 which isadapted to be connected to the unsprung mass of vehicle 10. The upperend of reserve tube 36 is attached to rod guide assembly 50. Base valveassembly 38 is disposed between lower working chamber 46 and reservoirchamber 52 to control the flow of fluid between chambers 46 and 52. Whenshock absorber 20 extends in length, an additional volume of fluid isneeded in lower working chamber 46 due to the “rod volume” concept.Thus, fluid will flow from reservoir chamber 52 to lower working chamber46 through base valve assembly 38 as detailed below. When shock absorber20 compresses in length, an excess of fluid must be removed from lowerworking chamber 46 due to the “rod volume” concept. Thus, fluid willflow from lower working chamber 46 to reservoir chamber 52 through basevalve assembly 38 as detailed below.

Baffle 40 extends concentrically between pressure tube 30 and reservetube 36. An upper end of baffle 40 is attached to rod guide assembly 50.An attachment mechanism 55 may include a hook, a snap-fit, a press fitor another suitable arrangement. In addition, the upper end of thebaffle 40 includes a collar 57 that extends radially outwardly. Thereserve tube 36 has a transition 59 where the diameter of the reservetube 36 decreases. The collar 57 of the baffle 40 contacts thetransition 59 of the reserve tube 36 to lock the baffle 40 in place andprevent the baffle 40 from moving axially relative to the reserve tube36 and the rod guide assembly 50. Alternatively, the baffle 40 may bepress-fit into the reserve tube 36 or welded to the reserve tube 36. Alower distal end of baffle 40 is shown unsupported and spaced apart frompressure tube 30, reserve tube 36 and base valve assembly 38.Alternatively, a support structure may be connected to the lower distalend of the baffle. The lower distal end of baffle 40 extends intoreservoir chamber 52 to such an extent to assure that the end maintainscontinuous contact with liquid fluid positioned within reservoir chamber52. More particularly, a baffle channel 56 exists between an outercylindrical surface of pressure tube 30 and an inner cylindrical surfaceof baffle 40. This annular space is completely filled with liquid at alltimes of operation of shock absorber 20.

A portion of reservoir chamber 52 positioned between an outercylindrical surface of baffle 40 and an internal cylindrical surface ofreserve tube 36 contains liquid fluid such as an oil in the lower regionthat at least includes the distal lower end of baffle 40. A pressurizedgas is positioned within an upper portion of reservoir chamber 52. Ano-ring 58 disposed along the collar 57 of the baffle 40 seals the upperend of baffle 40 to reserve tube 36. Other structures useful forproviding sealing attachment, including a press fit or a weld, arecontemplated as being within the scope of the present disclosure.

Referring now to FIG. 3, piston assembly 32 comprises a piston body 60,a compression valve assembly 62 and a rebound valve assembly 64.Compression valve assembly 62 is assembled against a shoulder 66 onpiston rod 34. Piston body 60 is assembled against compression valveassembly 62 and rebound valve assembly 64 is assembled against pistonbody 60. A nut 68 secures these components to piston rod 34.

Piston body 60 defines a plurality of compression passages 70 and aplurality of rebound passages 72. Seal 48 includes a plurality of ribs74 which mate with a plurality of annular grooves 76 to retain seal 48during sliding movement of piston assembly 32.

Compression valve assembly 62 comprises a retainer 78, a valve disc 80and a spring 82. Retainer 78 abuts shoulder 66 on one end and pistonbody 60 on the other end. Valve disc 80 abuts piston body 60 and closescompression passages 70 while leaving rebound passages 72 open. Spring82 is disposed between retainer 78 and valve disc 80 to bias valve disc80 against piston body 60. During a compression stroke, fluid in lowerworking chamber 46 is pressurized causing fluid pressure to reactagainst valve disc 80. When the fluid pressure against valve disc 80overcomes the biasing load of spring 82, valve disc 80 separates frompiston body 60 to open compression passages 70 and allow fluid flow fromlower working chamber 46 to upper working chamber 44. Typically spring82 only exerts a light load on valve disc 80 and compression valveassembly 62 acts as a check valve between chambers 46 and 44. Thedamping characteristics for shock absorber 20 during a compressionstroke are controlled in part by base valve assembly 38 whichaccommodates the flow of fluid from lower working chamber 46 toreservoir chamber 52 due to the “rod volume” concept. During a reboundstroke, compression passages 70 are closed by valve disc 80.

Rebound valve assembly 64 is termed a passive valve assembly whichcomprises a spacer 84, a plurality of valve discs 86, a retainer 88 anda spring 90. Spacer 84 is threadingly received on piston rod 34 and isdisposed between piston body 60 and nut 68. Spacer 84 retains pistonbody 60 and compression valve assembly 62 while permitting thetightening of nut 68 without compressing either valve disc 80 or valvediscs 86. Retainer 78, piston body 60 and spacer 84 provide a continuoussolid connection between shoulder 66 and nut 68 to facilitate thetightening and securing of nut 68 to spacer 84 and thus to piston rod34. Valve discs 86 are slidingly received on spacer 84 and abut pistonbody 60 to close rebound passages 72 while leaving compression passages70 open. Retainer 88 is also slidingly received on spacer 84 and itabuts valve discs 86. Spring 90 is assembled over spacer 84 and isdisposed between retainer 88 and nut 68 which is threadingly received onspacer 84. Spring 90 biases retainer 88 against valve discs 86 and valvediscs 86 against piston body 60. When fluid pressure is applied to valvediscs 86, they will elastically deflect at the outer peripheral edge toopen rebound valve assembly 64. A shim is located between nut 68 andspring 90 to control the preload for spring 90 and thus the blow offpressure as described below. Thus, the calibration for the blow offfeature of rebound valve assembly 64 is separate from the calibrationfor compression valve assembly 62.

During a rebound stroke, fluid in upper working chamber 44 ispressurized causing fluid pressure to react against valve discs 86.Prior to the deflecting of valve discs 86, a bleed flow of fluid flowsthrough a bleed passage defined between valve discs 86 and piston body60. When the fluid pressure reacting against valve discs 86 overcomesthe bending load for valve discs 86, valve discs 86 elastically deflectopening rebound passages 72 allowing fluid flow from upper workingchamber 44 to lower working chamber 46. The strength of valve discs 86and the size of rebound passages will determine the dampingcharacteristics for shock absorber 20 in rebound. When the fluidpressure within upper working chamber 44 reaches a predetermined level,the fluid pressure will overcome the biasing load of spring 90 causingaxial movement of retainer 88 and the plurality of valve discs 86. Theaxial movement of retainer 88 and valve discs 86 fully opens reboundpassages 72 thus allowing the passage of a significant amount of dampingfluid thereby creating a blowing off of the fluid pressure which isrequired to prevent damage to shock absorber 20 and/or vehicle 10.

Referring to FIG. 4, base valve assembly 38 comprises a valve body 92, acompression valve assembly 94 and a rebound valve assembly 96.Compression valve assembly 94 and rebound valve assembly 96 are attachedto valve body 92 using a bolt 98 and a nut 100. The tightening of nut100 biases compression valve assembly 94 towards valve body 92. Valvebody 92 defines a plurality of compression passages 102 and a pluralityof rebound passages 104.

Compression valve assembly 94 is termed a passive valve assembly whichcomprises a plurality of valve discs 106 that are biased against valvebody 92 by bolt 98 and nut 100. During a compression stroke, fluid inlower working chamber 46 is pressurized and the fluid pressure withincompression passages 102 reacts against valve discs 106. Prior to thedeflection of valve discs 106, a bleed flow of fluid will flow through ableed passage defined between valve discs 106 and valve body 92. Thefluid pressure reacting against valve discs 106 will eventually opencompression valve assembly 94 by deflecting valve discs 106 in a mannersimilar to that described above for rebound valve assembly 64.Compression valve assembly 62 will allow fluid flow from lower workingchamber 46 to upper working chamber 44 and only the “rod volume” willflow through compression valve assembly 94. The damping characteristicsfor shock absorber 20 are determined in part by the design ofcompression valve assembly 94 of base valve assembly 38.

Rebound valve assembly 96 comprises a valve disc 108 and a valve spring110. Valve disc 108 abuts valve body 92 and closes rebound passages 104.Valve spring 110 is disposed between nut 100 and valve disc 80 to biasvalve disc 108 against valve body 92. During a rebound stroke, fluid inlower working chamber 46 is reduced in pressure causing fluid pressurein reservoir chamber 52 to react against valve disc 108. When the fluidpressure against valve disc 108 overcomes the biasing load of valvespring 110, valve disc 108 separates from valve body 92 to open reboundpassages 104 and allow fluid flow from reservoir chamber 52 to lowerworking chamber 46. Typically valve spring 110 exerts only a light loadon valve disc 108 and compression valve assembly 94 acts as a checkvalve between reservoir chamber 52 and lower working chamber 46. Thedamping characteristics for a rebound stroke are controlled in part byrebound valve assembly 64 as detailed above.

Referring now to FIGS. 5 and 6, rod guide assembly 50 is illustrated ingreater detail. Rod guide assembly 50 comprises a rod guide housing 120,a seal assembly 122, and an electromechanical valve assembly 126.

Rod guide housing 120 is assembled into pressure tube 30 and intoreserve tube 36. The rod guide housing 120 includes one or moredepressions 121 that are formed in the outer surface of the rod guidehousing 120. The upper end of the reserve tube 36 is crimped or formedinto the depressions 121 in the rod guide housing 120 to lock the rodguide housing 120 in place and prevent the rod guide housing 120 frommoving longitudinally relative to the reserve tube 36. Seal assembly 122is assembled to rod guide housing 120. A cap 128 is attached to the endof shock absorber 20. A bushing 130 assembled into rod guide housing 120accommodates for the sliding motion of piston rod 34 while alsoproviding for a seal for piston rod 34. A fluid passage 132 extendsthrough rod guide housing 120 to allow fluid communication between upperworking chamber 44 and electromechanical valve assembly 126 as discussedbelow.

Electromechanical valve assembly 126 is a two position valve assemblywhich has a different flow area in each of the two positions.Electromechanical valve assembly 126 comprises a valve housing 140, asleeve 142, a spool 144, a spring 146 and a coil assembly 148. It shouldbe appreciated that valve housing 140 may be integral to rod guidehousing 120. Valve housing 140 defines a valve inlet 150 which is incommunication with upper working chamber 44 through fluid passage 132and a valve outlet 152 which is in fluid communication with bafflechannel 56. At least part of the valve outlet 152 is defined by achamfer 153 in the pressure tube adapter 51. Fluid exits theelectromechanical valve assembly 126 moving in an axial direction. Thechamfer 153 of the pressure tube adapter 51 changes the fluid flowexiting the electromechanical valve assembly 126 to a radial direction.The fluid flow then turns again back to a longitudinal direction as itflows through the baffle channel 56. This non-linear, tortuous fluidflow path through the valve outlet 152 reduces foaming of the fluid inthe valve outlet 152. It should be appreciated that the chamfer 153 ofthe pressure tube adapter 51 may be replaced by other structures. By wayof example and without limitation, the chamfer 153 of the pressure tubeadapter 51 may be replaced by a radially extending channel in thepressure tube adapter 51. While this embodiment and other embodimentsdescribed later include spring 146 in the electromechanical valveassemblies, it is within the scope of the present disclosure to useelectromechanical valve assemblies that do not include spring 146.Electromechanical valve assemblies that do not include spring 146 aremoved between their two positions by reversing the current or reversingthe polarity of the power provided to the electromechanical valveassembly. It is also contemplated that other electromechanical valvesmay be implemented into the shock absorber of the present disclosure.For example, a suitable alternative valve may include a side inlet and abottom outlet.

Sleeve 142 is disposed within valve housing 140. Sleeve 142 defines anannular inlet chamber 154 which is in communication with valve inlet 150and a pair of annular outlet chambers 156 and 158 which are incommunication with valve outlet 152. It should be appreciated thatalternate configurations having only one outlet are within the scope ofthe present disclosure. The outlet(s) may be directed axially instead ofthe radial orientation depicted.

Spool 144 is slidingly received within sleeve 142 and axially travelswithin sleeve 142 between coil assembly 148 and a stop puck 160 disposedwithin sleeve 142. Spring 146 biases spool 144 away from coil assembly148 and towards stop puck 160. A shim 162 is disposed between coilassembly 148 and sleeve 142 to control the amount of axial motion forspool 144. A first O-ring seals the interface between stop puck 160,sleeve 142 and valve housing 140. A second O-ring seals the interfacebetween coil assembly 148, sleeve 142 and rod guide housing 120.

Spool 144 defines a first flange 164 which controls fluid flow betweenannular inlet chamber 154 and annular outlet chamber 156 and a secondflange 166 that controls fluid flow between annular inlet chamber 154and annular outlet chamber 158. Flanges 164 and 166 thus control fluidflow from upper working chamber 44 to reservoir chamber 52. The numberof flanges depends on the configuration of the outlet. One or moreflanges may be used.

Coil assembly 148 is disposed within sleeve 142 to control the axialmovement of spool 144. The wiring connections for coil assembly 148 canextend through rod guide housing 120, through sleeve 142, through valvehousing 140 and/or through reserve tube 36. When there is no powerprovided to coil assembly 148, the damping characteristics will bedefined by the flow area of electromechanical valve assembly 126 in itsfirst position, piston assembly 32 and base valve assembly 38. Themovement of spool 144 is controlled by supplying power to coil assembly148 to move electromechanical valve assembly 126 to its second position.Electromechanical valve assembly 126 can be kept in its second positionby continuing to supply power to coil assembly 148 or by providing meansfor retaining electromechanical valve assembly 126 in its secondposition and discontinuing the supply of power to coil assembly 148. Themeans for retaining electromechanical valve assembly 126 in its secondposition can include mechanical means, magnetic means or other meansknown in the art. Once in its second position, movement to the firstposition can be accomplished by terminating power to coil assembly 148or by reversing the current or reversing the polarity of the powersupplied to coil assembly 148 to overcome the retaining means. Theamount of flow through electromechanical valve assembly 126 has discretesettings for flow control in both the first position and the secondposition.

While the present disclosure is described using only oneelectromechanical valve assembly 126, it is within the scope of thedisclosure to use a plurality of electromechanical valve assemblies 126.When multiple electromechanical valve assemblies 126 are used, the totalflow area through the plurality of electromechanical valve assemblies126 can be set at a specific number of total flow areas depending on theposition of each individual electromechanical valve assembly 126. Thespecific number of total flow areas can be defined as being 2^(n) flowareas where n is the number of electromechanical valve assemblies 126.For example, if there are four electromechanical valve assemblies 126,the number of total flow areas available would be 2⁴ or sixteen flowareas.

Referring to FIG. 7, the working principles of shock absorber 20 duringa compression stroke are depicted. A compression stroke includesadvancing piston rod 34 into pressure tube 30. As piston rod 34 istranslated, it enters pressure tube 30 and displaces a volume of oilequal to the rod volume. A primary oil flow Q1 passes through therestrictions in base valve assembly 38. At the same time, an annularvolume Q1′ flows in an unrestricted manner through compression valveassembly 62 to replenish the volume of oil within upper working chamber44. If one or more of electromechanical valve assemblies 126 are in anOPEN state, then a secondary oil flow Q2 occurs in parallel with theprimary oil flow Q1. The secondary oil flow(s) Q2 are restricted byorifice areas associated with each of electromechanical valve assemblies126.

As a result of the flows Q1 and Q2, a high pressure P1 occurs withinlower working chamber 46 of pressure tube 30 between base valve assembly38 and piston assembly 32. A lower pressure P2′ occurs below the basevalve assembly 38 due to the pressure differential (P1>P2′). A lowerpressure occurs above the piston assembly 32 due to the pressuredifferential (P1>P1′). Likewise, a lower pressure P2″ occurs after theorifice restrictions associated with each electromechanical valveassembly 126 due to the pressure differential (P1′>P2″). Additionalpressure differentials may be associated with each electromechanicalvalve assembly 126 if there are any internal flow restrictions withinthe electromechanical valve assemblies 126, in which case a lowerpressure P3″ occurs after electromechanical valve assemblies 126 due tothe pressure differential (P2″>P3″).

The secondary oil flow Q2 continues within baffle channel 56 and rejoinsthe primary oil flow Q1 in reservoir chamber 52 in order forQtotal=(Q1+Q2). A pressure P3′ at the bottom of baffle 40 and after basevalve assembly 38 will be equal to the gas charge pressure Pg inreservoir chamber 52 (i.e., P3″>P3′=Pg).

Referring to FIG. 8, during a rebound stroke (or extension stroke) ofthe shock absorber, piston rod 34 exits from pressure tube 30 anddisplaces a volume of oil equal to the rod volume. The primary oil flowQ1 passes through the restrictions in piston assembly 32. At the sametime, rod volume Q1′ flows unrestricted through base valve assembly 38to replenish the volume of oil within the lower portion of pressure tube30 between piston assembly 32 and base valve assembly 38. If one or moreelectromechanical valve assemblies 126 are in the OPEN state, then asecondary oil flow Q2 occurs in parallel with the primary oil flow Q1.The secondary oil flow(s) Q2 are restricted by orifice areas associatedwith each of the electromechanical valve assemblies 126.

As a result of the flows Q1 and Q2, high pressure P1 occurs within theworking chamber of pressure tube 30 between piston assembly 32 and rodguide assembly 50. A lower pressure P1′ occurs below piston assembly 32due to the pressure differential (P1>P1′) and (P2′>P1′). Likewise, alower pressure P2″ occurs after the orifice restrictions associated witheach electromechanical valve assembly 126 due to the pressuredifferential (P1>P2″). There may be additional pressure differentialsassociated with each electromechanical valve assembly 126 if there areany internal flow restrictions within electromechanical valve assemblies126. In which case, a lower pressure P3″ occurs after electromechanicalvalve assemblies 126 due to the pressure differential (P2″>P3″).

The secondary oil flow Q2 continues within the baffle channel 56 andrejoins the primary oil flow Q1 in the reservoir chamber 52 in order forQtotal=(Q1+Q2). The pressure P3′ at the bottom of baffle 40 and afterbase valve assembly 38 will be equal to the gas charge pressure Pg inthe reservoir chamber 52 (i.e., P3″>P3′=Pg).

Since baffle 40 is sealed at the upper end by O-ring 58 or anothersealing method, the pressure at the upper end of baffle 40 is alwayshigher than the pressure at the lower end of baffle 40 within reservoirchamber 52 (i.e., P3″>P3′=Pg). The oil level within reservoir chamber 52is defined to always remain above the lower end of baffle 40 duringtotal stroke of the shock absorber from extension to compression. As aresult, baffle 40 mitigates the risk for aeration or lag in dampingforce since P1>P2″>P3″>P3′=Pg and Qtotal=(Q1+Q2).

While not shown here with an illustration, another embodiment of thedisclosure includes individual baffles for each electromechanical valveassembly 126. This embodiment would function in the same manner asdescribed previously. The only difference is packaging of the baffles.The individual baffles would have a defined diameter to allow sufficientoil flow rate Q2 (for example, 8mm inside diameter). Each baffle wouldbe sealed at the outlet of each electromechanical valve assembly 126using an elastomeric seal, press fit, weld, or other means known in theart. Similarly, the oil level within the reservoir chamber 52 would bedefined to always remain above the lower end of the baffles during totalstroke of the shock absorber from extension to compression. As a result,the baffles will mitigate the risk for aeration or lag in damping forcesince P1>P2″>P3″>P3′=Pg and Qtotal=(Q1+Q2).

FIGS. 9-11 illustrate another alternative embodiment where the shockabsorber 20 includes a baffle 240 with a plurality of grooves 242 a, 242b, 242 c, 242 d that extend helically along an outer surface 246 of thebaffle 240. In the illustrated embodiment, the plurality of grooves 242a, 242 b, 242 c, 242 d extend from an upper end 254 of the baffle 240 toa lower end 255 of the baffle 240; however, the plurality of grooves 242a, 242 b, 242 c, 242 d may alternatively extend along only a part of thelongitudinal length of the baffle 240. As shown in FIGS. 9-11, thebaffle 240 extends annularly about the pressure tube 30 and is disposedradially between the pressure tube 30 and the reserve tube 36. However,it should be appreciated that the baffle 240 may alternatively extendless than 360 degrees about the pressure tube 30. For example, thebaffle 240 may include a separation (i.e. a gap) that extendslongitudinally from the upper end 254 to the lower end 255 of the baffle240. In another alternative embodiment, the baffle 240 may includemultiple separations that break the baffle 240 up into discrete sectionsthat extend radially about only a portion of the pressure tube 30.

In the illustrated embodiment, an inner surface 244 of the baffle 240 isa smooth cylindrical surface and is arranged in contact with the outercylindrical surface of the pressure tube 30 to support the baffle 240concentrically on the pressure tube 30. Alternatively, the inner surface244 of the baffle 240 may be spaced radially outward of the outercylindrical surface of the pressure tube 30 and the baffle 240 may besupported by the reserve tube 36.

Together, grooves 242 a and 242 c define a baffle channel 256 in theform of a first helical passageway 258 a and a third helical passageway258 c. In the illustrated embodiment, the first and third helicalpassageways 258 a, 258 c extend from the upper end 254 of the baffle 240to the lower end 255 of the baffle 240 and radially between the innercylindrical surface of the reserve tube 36 and the outer surface 246 ofthe baffle 240 in grooves 242 a and 242 c. However, it should beappreciated that the first and third helical passageways 258 a, 258 cmay extend along only part of the longitudinal length of the baffle 240.A reservoir chamber 252 is disposed between the pressure tube 30 and thereserve tube 36 adjacent to the lower end 255 of the baffle 240. Grooves242 b and 242 d are disposed in fluid communication with the reservoirchamber 252 only. In other words, the grooves 242 b and 242 d are opento the reservoir chamber 252 at the lower end 255 of the baffle 240 andare closed at the upper end 254 of the baffle 240. Accordingly, grooves242 b and 242 d also define part of the reservoir chamber 252 in theform of a second helical passageway 258 b and a fourth helicalpassageway 258 d. A liquid fluid such as an oil is contained in a lowerregion of the reservoir chamber 252 and a pressurized gas is containedin an upper portion of reservoir chamber 252. In embodiments where theinner surface 244 of the baffle 240 is spaced radially outward of theouter cylindrical surface of the pressure tube 30, the space between thepressure tube 30 and the inner surface 244 of the baffle 240 may alsoform part of the reservoir chamber 252.

The passageways 258 a, 258 b, 258 c, 258 d are non-linear and provide atortuous fluid flow path along the outer surface 246 of the baffle 240.Because all of the passageways 258 a, 258 b, 258 c, 258 d have a helicalshape, the passageways 258 a, 258 b, 258 c, 258 d have both alongitudinal component and a circumferential component. The plurality ofgrooves 242 a, 242 b, 242 c, 242 d and therefore the helical passageways258 a, 258 b, 258 c, 258 d are radially spaced about the baffle 240 suchthat threads 260 a, 260 b, 260 c, 260 d are formed in the baffle 240that extend radially outwardly from the baffle 240 between the pluralityof grooves 242 a, 242 b, 242 c, 242 d. The outer surface 246 of thebaffle 240 at the threads 260 a, 260 b, 260 c, 260 d contacts the innercylindrical surface of the reserve tube 36 to support the baffle 240concentrically without the reserve tube 36. Because the outer surface246 of the baffle 240 at the threads 260 a, 260 b, 260 c, 260 d contactsthe inner cylindrical surface of the reserve tube 36, the helicalpassageways 258 a, 258 b, 258 c, 258 d defined by the plurality ofgrooves 242 a, 242 b, 242 c, 242 d are separate from one another (i.e.,fluid flowing through the first helical passageway 258 a is isolatedfrom fluid flowing through the second helical passageway 258 b along atleast part of the longitudinal length of the baffle 240).

In the illustrated embodiment, both the first and third helicalpassageways 258 a and 258 c are disposed in fluid communication with atleast one electromechanical valve assembly 126 and the reservoir chamber252. Alternatively, the shock absorber 20 may include oneelectromechanical valve assembly for each of the first and third helicalpassageways 258 a and 258 c. When the at least one electromechanicalvalve assembly 126 is in the OPEN state, fluid flows through the firstand third helical passageways 258 a and 258 c along flow direction F1.The second and fourth helical passageways 258 b and 258 d are disposedin fluid communication with only the reservoir chamber 252. The secondand fourth helical passageways 258 b and 258 d are closed (i.e. notopen) to the one or more electromechanical valve assemblies 126. Fluidin the reservoir chamber 252 flows in the opposite direction in thesecond and fourth helical passageways 258 b and 258 d along flowdirection F2. In another embodiment, all four helical passageways 258 a,258 b, 258 c, 258 d may communicate with one electromechanical valveassemblies 126.

Transfer passages 262 extend through the baffle 240 and are disposed influid communication with the valve outlet 152 and the first and thirdhelical passageways 258 a and 258 c. Fluid from the valve outlet 152flows into the first and third helical passageways 258 a and 258 c andto the reservoir chamber 252. The baffle 240 may optionally include aclocking feature 264 that ensures proper positioning (i.e., indexing) ofthe baffle 240, where the first and third helical passageways 258 a and258 c are circumferentially aligned with the valve outlet(s) 152 of theone or more electromechanical valve assemblies 126. By way of exampleand without limitation, the clocking feature 264 may be provided in theform of a notch in the upper end 254 of the baffle 240 that engages atab on the rod guide assembly 50. In the illustrated example, the one ormore electromechanical valve assemblies 126 are located in the rod guideassembly 50. However, other configurations are possible. For example,the one or more electromechanical valve assemblies 126 may be mountedexternally on the reserve tube 36. Even though the one or moreelectromechanical valve assemblies 126 are external to the reserve tube36, the inside passages of the one or more electromechanical valveassemblies 126 are disposed in fluid communication with the bafflechannel 256 and the reservoir chamber 252. As a result, the one or moreelectromechanical valve assemblies 126 are operable to control fluidflow from the baffle channel 256 to the reservoir chamber 252.

Advantageously, the first and third helical passageways 258 a and 258 cdefined by grooves 242 a and 242 c transport fluid from the valve outlet152 of the electromechanical valve assembly 126 to the reservoir chamber252 with minimal foaming (i.e., bubbling). The subject design minimizesthe volume of the baffle channel 256. The subject design also maximizesthe volume of the reservoir chamber 252 due to the added volume ofsecond and fourth helical passageways 258 b and 258 d. In the exampleshown in FIGS. 9-11, the plurality of grooves 242 a, 242 b, 242 c, 242 dhave a rectangular cross-sectional shape; however, it should beappreciated that other shapes are possible. In addition, it should beappreciated that the number of grooves and therefore the number ofhelical passageways may vary from the four grooves 242 a, 242 b, 242 c,242 d and the four helical passageways 258 a, 258 b, 258 c, 258 d shownin the illustrated embodiment.

FIGS. 12-15 illustrate another alternative embodiment where the shockabsorber 20 includes a baffle 340 with a plurality of grooves 342 a, 342b, 342 c, 342 d that extend helically along an inner surface 344 of thebaffle 340. In the illustrated embodiment, the plurality of grooves 342a, 342 b, 342 c, 342 d extend from an upper end 354 of the baffle 340 toa lower end 355 of the baffle 340; however, the plurality of grooves 342a, 342 b, 342 c, 342 d may alternatively extend along only a part of thelongitudinal length of the baffle 340. As shown in FIGS. 12-15, thebaffle 340 extends annularly about the pressure tube 30 and is disposedradially between the pressure tube 30 and the reserve tube 36. However,it should be appreciated that the baffle 340 may alternatively extendless than 360 degrees about the pressure tube 30. For example, thebaffle 340 may include a separation (i.e. a gap) that extendslongitudinally from the upper end 354 to the lower end 355 of the baffle340. In another alternative embodiment, the baffle 340 may includemultiple separations that break the baffle 340 up into discrete sectionsthat extend radially about only a portion of the pressure tube 30.

Together, grooves 342 a and 342 c define a baffle channel 356 in theform of a first helical passageway 358 a and a third helical passageway358 c. In the illustrated embodiment, the first and third helicalpassageways 358 a, 358 c extend from the upper end 354 of the baffle 340to the lower end 355 of the baffle 340 and radially between the outercylindrical surface of the pressure tube 30 and the inner surface 344 ofthe baffle 340 in grooves 342 a and 342 c. However, it should beappreciated that the first and third helical passageways 358 a, 358 cmay extend along only part of the longitudinal length of the baffle 340.

In accordance with this embodiment, the outer surface 346 of the baffle340 is a smooth cylindrical surface and is spaced radially inward of theinner cylindrical surface of the reserve tube 36. A reservoir chamber352 is disposed between the pressure tube 30 and the reserve tube 36adjacent to the lower end 355 of the baffle 340 and between the outersurface 346 of the baffle 340 and the inner cylindrical surface of thereserve tube 36. Grooves 342 b and 342 d are disposed in fluidcommunication with the reservoir chamber 352 only. In other words, thegrooves 342 b and 342 d are open to the reservoir chamber 352 at thelower end 355 of the baffle 340 and are closed at the upper end 354 ofthe baffle 340. Accordingly, grooves 342 b and 342 d also define part ofthe reservoir chamber 352 in the form of a second helical passageway 358b and a fourth helical passageway 358 d. A liquid fluid such as an oilis contained in a lower region of the reservoir chamber 352 and apressurized gas is contained in an upper portion of reservoir chamber352.

The passageways 358 a, 358 b, 358 c, 358 d are non-linear and provide atortuous fluid flow path along the inner surface 344 of the baffle 340.Because all of the passageways 358 a, 358 b, 358 c, 358 d have a helicalshape, the passageways 358 a, 358 b, 358 c, 358 d have both alongitudinal component and a circumferential component. The plurality ofgrooves 342 a, 342 b, 342 c, 342 d and therefore the helical passageways358 a, 358 b, 358 c, 358 d are radially spaced about the baffle 340 suchthat threads 360 a, 360 b, 360 c, 360 d are formed in the baffle 340that extend radially inwardly from the baffle 340 between the pluralityof grooves 342 a, 342 b, 342 c, 342 d. The inner surface 344 of thebaffle 340 at the threads 360 a, 360 b, 360 c, 360 d contacts the outercylindrical surface of the pressure tube 30 and supports the baffle 340concentrically on the pressure tube 30. Because the inner surface 346 ofthe baffle 340 at the threads 360 a, 360 b, 360 c, 360 d contacts theouter cylindrical surface of the pressure tube 30, the helicalpassageways 358 a, 358 b, 358 c, 358 d defined by the plurality ofgrooves 342 a, 342 b, 342 c, 342 d are separate from one another (i.e.,fluid flowing through the first helical passageway 358 a is isolatedfrom fluid flowing through the second helical passageway 358 b along atleast part of the longitudinal length of the baffle 340).

Both the first and third helical passageways 358 a and 358 c aredisposed in fluid communication with at least one electromechanicalvalve assembly 126 and the reservoir chamber 352. Alternatively, theshock absorber 20 may include one electromechanical valve assembly foreach of the first and third helical passageways 358 a and 358 c. Whenthe at least one electromechanical valve assembly 126 is in the OPENstate, fluid flows through the first and third helical passageways 358 aand 358 c along flow direction F1. The second and fourth helicalpassageways 358 b and 358 d are disposed in fluid communication withonly the reservoir chamber 352. The second and fourth helicalpassageways 358 b and 358 d are closed (i.e. not open) to the one ormore electromechanical valve assemblies 126. Fluid in the reservoirchamber 352 flows in the opposite direction in the second and fourthhelical passageways 358 b and 358 d along flow direction F2.

Fluid from the valve outlet 152 flows into the first and third helicalpassageways 358 a and 358 c and to the reservoir chamber 352. The baffle340 may optionally include a clocking feature 364 that ensures properpositioning (i.e., indexing) of the baffle 340, where the first andthird helical passageways 358 a and 358 c are circumferentially alignedwith the valve outlet(s) 152 of the one or more electromechanical valveassemblies 126. By way of example and without limitation, the clockingfeature 364 may be provided in the form of a notch in the upper end 354of the baffle 340 that engages a tab on the rod guide assembly 50. Inthe illustrated example, the one or more electromechanical valveassemblies 126 are located in the rod guide assembly 50. However, otherconfigurations are possible. For example, the one or moreelectromechanical valve assemblies 126 may be mounted externally on thereserve tube 36. Even though the one or more electromechanical valveassemblies 126 are external to the reserve tube 36, the inside passagesof the one or more electromechanical valve assemblies 126 are disposedin fluid communication with the baffle channel 356 and the reservoirchamber 352. As a result, the one or more electromechanical valveassemblies 126 are operable to control fluid flow from the bafflechannel 356 to the reservoir chamber 352.

Advantageously, the first and third helical passageways 358 a and 358 cdefined by grooves 342 a and 342 c transport fluid from theelectromechanical valve assembly 126 to the reservoir chamber 352 withminimal foaming (i.e., bubbling). The subject design minimizes thevolume of the baffle channel 356. The subject design also maximizes thevolume of the reservoir chamber 352 due to the added volume of secondand fourth helical passageways 358 b and 358 d. In the example shown inFIGS. 12-15, the plurality of grooves 342 a, 342 b, 342 c, 342 d have arectangular cross-sectional shape; however, it should be appreciatedthat other shapes are possible. In addition, it should be appreciatedthat the number of grooves and therefore the number of helicalpassageways may vary from the four grooves 342 a, 342 b, 342 c, 342 dand the four helical passageways 358 a, 358 b, 358 c, 358 d shown in theillustrated embodiment.

It should be appreciated that an alternative embodiment is possiblewhere the embodiment of the shock absorber 20 includes a baffle thatcombines the features of the baffle 240 illustrated in FIGS. 9-11 andthe baffle 340 illustrated in FIGS. 12-15. In accordance with thisembodiment, the outer surface of the baffle may include helicalpassageways 258 a, 258 b, 258 c, 258 d along only a first portion of thelongitudinal length of the baffle and the inner surface of the bafflemay include helical passageways 358 a, 358 b, 358 c, 358 d along only asecond portion of the longitudinal length of the baffle. Holes may beprovided in the baffle so fluid can flow through the baffle andcommunicate between the helical passageways 258 a, 258 b, 258 c, 258 don the outer surface of the baffle and the helical passageways 358 a,358 b, 358 c, 358 d on the inner surface of the baffle. In accordancewith this design, the inner surface of the baffle may be a smoothcylindrical surface along the first portion of the longitudinal lengthof the baffle and the outer surface of the baffle may be a smoothcylindrical surface along the second portion of the longitudinal lengthof the baffle.

FIGS. 16-19 illustrate another alternative embodiment where the shockabsorber 20 includes a baffle 440 that has a plurality of inner grooves442 a, 442 b, 442 c, 442 d and a plurality of outer grooves 443 a, 443b, 443 c, 443 d. The plurality of inner grooves 442 a, 442 b, 442 c, 442d extend longitudinally along an inner surface 444 of the baffle 440 andthe plurality of outer grooves 443 a, 443 b, 443 c, 443 d extendlongitudinally along an outer surface 446 of the baffle 440. Theplurality of inner grooves 442 a, 442 b, 442 c, 442 d and a plurality ofouter grooves 443 a, 443 b, 443 c, 443 d may extend from the upper end454 of the baffle 440 to the lower end 456 of the baffle 440.Alternatively, the plurality of inner grooves 442 a, 442 b, 442 c, 442 dand a plurality of outer grooves 443 a, 443 b, 443 c, 443 d may extendalong only part of the longitudinal length of the baffle 440. As shownin FIGS. 16-19, the baffle 440 extends annularly about the pressure tube30 and is disposed radially between the pressure tube 30 and the reservetube 36. However, it should be appreciated that the baffle 440 mayalternatively extend less than 360 degrees about the pressure tube 30.For example, the baffle 440 may include a separation (i.e. a gap) thatextends longitudinally from the upper end 454 to the lower end 455 ofthe baffle 440. In another alternative embodiment, the baffle 440 mayinclude multiple separations that break the baffle 440 up into discretesections that extend radially about only a portion of the pressure tube30.

Together, the plurality of inner grooves 442 a, 442 b, 442 c, 442 ddefine a baffle channel 456 in the form of four inner helicalpassageways 458 a, 458 b, 458 c, 458 d. The inner helical passageways458 a, 458 b, 458 c, 458 d extend helically along the baffle 440 fromthe upper end 454 of the baffle 440 to the lower end 455 of the baffle440 and radially between the outer cylindrical surface of the pressuretube 30 and the inner surface 444 of the baffle 440 in the inner grooves442 a, 442 b, 442 c, 442 d.

The plurality of outer grooves 443 a, 443 b, 443 c, 443 d define fourouter helical passageways 459 a, 459 b, 459 c, 459 d. The outer helicalpassageways 459 a, 459 b, 459 c, 459 d extend helically along the baffle440 from the upper end 454 of the baffle 440 to the lower end 456 of thebaffle 440. A reservoir chamber 452 is disposed between the pressuretube 30 and the reserve tube 36 adjacent to the lower end 455 of thebaffle 440. The outer helical passageways 459 a, 459 b, 459 c, 459 d aredisposed in fluid communication with the reservoir chamber 452 only. Inother words, the plurality of outer grooves 443 a, 443 b, 443 c, 443 dare open to the reservoir chamber 452 at the lower end 455 of the baffle440 and are closed at the upper end 454 of the baffle 440. Accordingly,the outer helical passageways 459 a, 459 b, 459 c, 459 d form part ofthe reservoir chamber 452. A liquid fluid such as an oil is contained ina lower region of the reservoir chamber 452 and a pressurized gas iscontained in an upper portion of reservoir chamber 452.

The plurality of inner grooves 442 a, 442 b, 442 c, 442 d and theplurality of outer grooves 443 a, 443 b, 443 c, 443 d and therefore theinner helical passageways 458 a, 458 b, 458 c, 458 d and the outerhelical passageways 459 a, 459 b, 459 c, 459 d are non-linear andprovide a tortuous fluid flow path along the inner surface 444 and theouter surface 446 of the baffle 440. Because all of the inner helicalpassageways 458 a, 458 b, 458 c, 458 d and the outer helical passageways459 a, 459 b, 459 c, 459 d have a helical shape, the inner helicalpassageways 458 a, 458 b, 458 c, 458 d and the outer helical passageways459 a, 459 b, 459 c, 459 d have both a longitudinal component and acircumferential component.

The plurality of inner grooves 442 a, 442 b, 442 c, 442 d and thereforethe inner helical passageways 458 a, 458 b, 458 c, 458 d are radiallyspaced about the baffle 440 such that inner threads 460 a, 460 b, 460 c,460 d are formed in the baffle 440 that extend radially inwardly fromthe baffle 440 between the plurality of inner grooves 442 a, 442 b, 442c, 442 d. The inner surface 444 of the baffle 440 contacts the outercylindrical surface of the pressure tube 30 at the threads 460 a, 460 b,460 c, 460 d and supports the baffle 440 concentrically on the pressuretube 30. Because the inner surface 444 of the baffle 440 contacts theouter cylindrical surface of the pressure tube 30 at the threads 460 a,460 b, 460 c, 460 d, the inner helical passageways 458 a, 458 b, 458 c,458 d are separate from one another.

The plurality of outer grooves 443 a, 443 b, 443 c, 443 d and thereforethe outer helical passageways 459 a, 459 b, 459 c, 459 d are radiallyspaced about the baffle 440 such that outer threads 461 a, 461 b, 461 c,461 d are formed in the baffle 440 that extend radially inwardly fromthe baffle 440 between the plurality of outer grooves 443 a, 443 b, 443c, 443 d. The outer surface 446 of the baffle 440 contacts the innercylindrical surface of the reserve tube 36 at the threads 461 a, 461 b,461 c, 461 d and supports the baffle 440 concentrically within thereserve tube 36. Because the outer surface 446 of the baffle 440contacts the inner cylindrical surface of the reserve tube 36 at thethreads 461 a, 461 b, 461 c, 461 d, the outer helical passageways 459 a,459 b, 459 c, 459 d are separate from one another.

The electromechanical valve assembly 126 is disposed in fluidcommunication with each of the inner helical passageways 458 a, 458 b,458 c, 458 d. When the electromechanical valve assembly 126 is in theOPEN state, fluid flows through the inner helical passageways 458 a, 458b, 458 c, 458 d along flow direction F1 to the reservoir chamber 452,where the fluid then flows in the opposite direction in the outerhelical passageways 459 a, 459 b, 459 c, 459 d along flow direction F2.Alternatively, the shock absorber 20 may include one electromechanicalvalve assembly for each of the inner helical passageways 458 a, 458 b,458 c, 458 d.

Fluid from the valve outlet 152 flows into the inner helical passageways458 a, 458 b, 458 c, 458 d and to the reservoir chamber 452. The baffle440 may optionally include a clocking feature 464 that ensures properpositioning (i.e., indexing) of the baffle 440, where the inner helicalpassageways 458 a, 458 b, 458 c, 458 d are circumferentially alignedwith the valve outlet(s) 152 of the one or more electromechanical valveassemblies 126. By way of example and without limitation, the clockingfeature 464 may be provided in the form of a notch in the upper end 454of the baffle 440 that engages a tab on the rod guide assembly 50. Inthe illustrated example, the one or more electromechanical valveassemblies 126 are located in the rod guide assembly 50. However, otherconfigurations are possible. For example, the one or moreelectromechanical valve assemblies 126 may be mounted externally on thereserve tube 36. Even though the one or more electromechanical valveassemblies 126 are external to the reserve tube 36, the inside passagesof the one or more electromechanical valve assemblies 126 are disposedin fluid communication with the baffle channel 456 and the reservoirchamber 452. As a result, the one or more electromechanical valveassemblies 126 are operable to control fluid flow from the bafflechannel 456 to the reservoir chamber 452.

Advantageously, the separate inner helical passageways 458 a, 458 b, 458c, 458 d defined by the plurality of inner grooves 442 a, 442 b, 442 c,442 d transport fluid from the electromechanical valve assembly 126 tothe reservoir chamber 452 with minimal foaming (i.e., bubbling). Thesubject design minimizes the volume of the baffle channel 456. Thesubject design also maximizes the volume of the reservoir chamber 452due to the added volume of the outer grooves 443 a, 443 b, 443 c, 443 d.In the example shown in FIGS. 16-19, the plurality of inner grooves 442a, 442 b, 442 c, 442 d and the plurality of outer grooves 443 a, 443 b,443 c, 443 d have a rectangular cross-sectional shape; however, itshould be appreciated that other shapes are possible. In addition, itshould be appreciated that the number of inner and outer grooves andtherefore the number of inner and outer helical passageways may varyfrom the four inner grooves 442 a, 442 b, 442 c, 442 d, four innerhelical passageways 458 a, 458 b, 458 c, 458 d, four outer grooves 443a, 443 b, 443 c, 443 d, and four outer helical passageways 459 a, 459 b,459 c, 459 d shown in the illustrated embodiment.

FIGS. 20-23 illustrate another alternative embodiment where the shockabsorber 20 includes a baffle 540 with a plurality of grooves 542 a, 542b that extend in a non-linear, serpentine (zig-zag) path along an outersurface 546 of the baffle 540. In the illustrated embodiment, theplurality of grooves 542 a, 542 b extend from an upper end 554 of thebaffle 540 to a lower end 555 of the baffle 540; however, the pluralityof grooves 542 a, 542 b may alternatively extend along only a part ofthe longitudinal length of the baffle 540. As shown in FIGS. 20-23, thebaffle 540 extends annularly about the pressure tube 30 and is disposedradially between the pressure tube 30 and the reserve tube 36. However,it should be appreciated that the baffle 540 may alternatively extendless than 360 degrees about the pressure tube 30. For example, thebaffle 540 may include a separation (i.e. a gap) that extendslongitudinally from the upper end 554 to the lower end 555 of the baffle540. In another alternative embodiment, the baffle 540 may includemultiple separations that break the baffle 540 up into discrete sectionsthat extend radially about only a portion of the pressure tube 30.

In the illustrated embodiment, an inner surface 544 of the baffle 540 isa smooth cylindrical surface and is arranged in contact with the outercylindrical surface of the pressure tube 30 to support the baffle 540concentrically on the pressure tube 30. Alternatively, the inner surface544 of the baffle 540 may be spaced radially outward of the outercylindrical surface of the pressure tube 30 and the baffle 540 may besupported by the reserve tube 36.

Groove 542 a defines a baffle channel 556 in the form of a firstnon-linear passageway 558 a. In the illustrated embodiment, the firstnon-linear passageway 558 extends from the upper end 554 of the baffle540 to the lower end 555 of the baffle 540 and radially between theinner cylindrical surface of the reserve tube 36 and the outer surface546 of the baffle 540 in groove 542 a. However, it should be appreciatedthat the first non-linear passageway 558 a may extend along only part ofthe longitudinal length of the baffle 540. A reservoir chamber 552 isdisposed between the pressure tube 30 and the reserve tube 36 adjacentto the lower end 555 of the baffle 540. Groove 542 b is disposed influid communication with the reservoir chamber 552 only. In other words,groove 542 b is open to the reservoir chamber 552 at the lower end 555of the baffle 540 and is closed at the upper end 554 of the baffle 540.Accordingly, groove 542 b defines part of the reservoir chamber 552 inthe form of a second non-linear passageway 558 b. A liquid fluid such asan oil is contained in a lower region of the reservoir chamber 552 and apressurized gas is contained in an upper portion of reservoir chamber552. In embodiments where the inner surface 544 of the baffle 540 isspaced radially outward of the outer cylindrical surface of the pressuretube 30, the space between the pressure tube 30 and the inner surface544 of the baffle 540 may also form part of the reservoir chamber 552.

The non-linear shape of the first and second passageways 558 a and 558 bprovide a tortuous fluid flow path along the outer surface 546 of thebaffle 540. Because the first and second passageways 558 a, 558 b have aserpentine shape, the first and second passageways 558 a, 558 b haveboth a longitudinal component and a circumferential component. Theplurality of grooves 542 a, 542 b and therefore the first and secondpassageways 558 a, 558 b are radially spaced about the baffle 540. Theouter surface 546 of the baffle 540 between grooves 542 a, 542 bcontacts the inner cylindrical surface of the reserve tube 36 to supportthe baffle 540 concentrically without the reserve tube 36. Because theouter surface 546 of the baffle 240 contacts the inner cylindricalsurface of the reserve tube 36 between the grooves 542 a, 542 b, thefirst and second passageways 558 a, 558 b are separate from one another(i.e., fluid flowing through the first passageway 558 a is isolated fromfluid flowing through the second passageway 558 b along at least part ofthe longitudinal length of the baffle 540).

In the illustrated embodiment, the first passageway 558 a is disposed influid communication with at least one electromechanical valve assembly126 and the reservoir chamber 552. When the at least oneelectromechanical valve assembly 126 is in the OPEN state, fluid flowsthrough the first passageway 558 a along flow direction F1. The secondpassageway 558 b is disposed in fluid communication with only thereservoir chamber 552. The second passageway 558 b is closed (i.e. notopen) to the electromechanical valve assemblies 126. Fluid in thereservoir chamber 552 flows in the opposite direction in the secondpassageway 558 b along flow direction F2.

Transfer passage 562 extends through the baffle 540, communicating fluidfrom the valve outlet 152 to the first passageway 558 a. Fluid from thevalve outlet 152 flows into the first passageway 558 a and to thereservoir chamber 552. The baffle 540 may optionally include a clockingfeature 564 that ensures proper positioning (i.e., indexing) of thebaffle 540, where the first passageway 558 a is circumferentiallyaligned with the valve outlet 152 of the one or more electromechanicalvalve assemblies 126. By way of example and without limitation, theclocking feature 564 may be provided in the form of a notch in the upperend 554 of the baffle 540 that engages a tab on the rod guide assembly50. In the illustrated example, the one or more electromechanical valveassemblies 126 are located in the rod guide assembly 50. However, otherconfigurations are possible. For example, the one or moreelectromechanical valve assemblies 126 may be mounted externally on thereserve tube 36. Even though the one or more electromechanical valveassemblies 126 are external to the reserve tube 36, the inside passagesof the one or more electromechanical valve assemblies 126 are disposedin fluid communication with the baffle channel 556 and the reservoirchamber 552. As a result, the one or more electromechanical valveassemblies 126 are operable to control fluid flow from the bafflechannel 556 to the reservoir chamber 552.

Advantageously, the first non-linear passageway 558 a defined by groove542 a transports fluid from the electromechanical valve assembly 126 tothe reservoir chamber 552 with minimal foaming (i.e., bubbling). Thesubject design minimizes the volume of the baffle channel 556. Thesubject design also maximizes the volume of the reservoir chamber 552due to the added volume of second non-linear passageway 558 b. In theexample shown in FIGS. 20-23, the plurality of grooves 542 a, 542 b havea rectangular cross-sectional shape; however, it should be appreciatedthat other shapes are possible. In addition, it should be appreciatedthat the number of grooves and therefore the number of non-linearpassageways may vary from the two grooves 542 a, 542 b and the twonon-linear passageways 558 a, 558 b shown in the illustrated embodiment.In yet another embodiment, both of the first and second non-linearpassageways 558 a, 558 b may be disposed in fluid communication with theone or more electromechanical valve assemblies 126. In accordance withthis embodiment, the inner surface 544 of the baffle 540 may be spacedradially outward of the outer cylindrical surface of the pressure tube30 such that the reservoir chamber 552 is positioned radially betweenthe pressure tube 30 and the baffle 540.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

1. A shock absorber comprising: a pressure tube having an inner surfacethat defines a working chamber and an outer surface opposite the innersurface of the pressure tube; a piston assembly attached to a piston rodand slidably disposed within the pressure tube, the piston assemblydividing the working chamber into an upper working chamber and a lowerworking chamber; a reserve tube disposed around the pressure tube, thereserve tube having an inner surface that faces the pressure tube and anouter surface opposite the inner surface of the reserve tube; a bafflepositioned radially between the pressure tube and the reserve tube todefine a baffle channel and a reservoir chamber between the pressuretube and the reserve tube; and at least one valve positioned in fluidcommunication with the upper working chamber and the baffle channel forcontrolling fluid flow between the upper working chambers and the bafflechannel, wherein the baffle channel includes a plurality of passagewaysthat are defined by grooves in the baffle together with at least one ofthe outer surface of the pressure tube and the inner surface of thereserve tube, at least one of the plurality of passageways disposed influid communication with the at least one valve and the reservoirchamber.
 2. The shock absorber of claim 1, wherein the plurality ofpassageways are non-linear and provide a tortuous fluid flow path alongthe baffle.
 3. The shock absorber of claim 2, wherein the grooves andthe plurality of passageways extend from an upper end of the baffle to alower end of the baffle.
 4. The shock absorber of claim 2, wherein theplurality of passageways includes a first passageway that is disposed influid communication with the at least one valve and the reservoirchamber and a second passageway that is disposed in fluid communicationwith only the reservoir chamber.
 5. The shock absorber of claim 2,wherein the plurality of passageways includes a first passageway that isdisposed in fluid communication with the at least one valve and thereservoir chamber and a second passageway that is disposed in fluidcommunication with the reservoir chamber and that is closed off from theat least one valve.
 6. The shock absorber of claim 2, wherein thegrooves extend helically along an inner surface of the baffle such thatthe grooves and the outer surface of the pressure tube cooperate todefine the plurality of passageways.
 7. The shock absorber of claim 2,wherein the grooves extend helically along an outer surface of thebaffle such that the grooves and the inner surface of the reserve tubecooperate to define the plurality of passageways.
 8. The shock absorberof claim 2, wherein the grooves include inner grooves and outer groovesand the plurality of passageways include inner passageways and outerpassageways, the inner grooves extending helically along an innersurface of the baffle such that the inner grooves and the outer surfaceof the pressure tube cooperate to define the inner passageways, and theouter grooves extending helically along an outer surface of the bafflesuch that the outer grooves and the inner surface of the reserve tubecooperate to define the outer passageways.
 9. The shock absorber ofclaim 8, wherein the inner passageways are disposed in fluidcommunication with the at least one valve and the reservoir chamber andthe outer passageways are disposed in fluid communication with only thereservoir chamber.
 10. The shock absorber of claim 2, wherein thegrooves extend in a serpentine path along an outer surface of the bafflesuch that the grooves and the inner surface of the reserve tubecooperate to define the plurality of passageways.
 11. A shock absorbercomprising: a pressure tube having an inner surface that defines aworking chamber and an outer surface opposite the inner surface of thepressure tube; a piston assembly attached to a piston rod and slidablydisposed within the pressure tube, the piston assembly dividing theworking chamber into an upper working chamber and a lower workingchamber; a reserve tube disposed around the pressure tube, the reservetube having an inner surface that faces the pressure tube and an outersurface opposite the inner surface of the reserve tube; a bafflepositioned radially between the pressure tube and the reserve tube todefine a baffle channel and a reservoir chamber between the pressuretube and the reserve tube; and at least one valve positioned in fluidcommunication with the upper working chamber and the baffle channel forcontrolling fluid flow between the upper working chambers and the bafflechannel, wherein the baffle channel includes a plurality of passagewaysthat are defined by grooves in the baffle together with at least one ofthe outer surface of the pressure tube and the inner surface of thereserve tube, the plurality of passageways having a non-linear shape toprovide a tortuous fluid flow path along the baffle, at least one of theplurality of passageways disposed in fluid communication with the atleast one valve and the reservoir chamber.
 12. The shock absorber ofclaim 11, wherein the baffle channel and the plurality of passagewaysare positioned radially between the pressure tube and the baffle. 13.The shock absorber of claim 11, wherein the baffle channel and theplurality of passageways are positioned radially between the reservetube and the baffle.
 14. The shock absorber of claim 11, wherein thebaffle is disposed in contact with and is supported by the pressuretube.
 15. The shock absorber of claim 11, wherein the baffle is disposedin contact with and is supported by the reserve tube.
 16. The shockabsorber of claim 11, wherein the at least one valve is positionedbetween the piston rod and the reserve tube.
 17. The shock absorber ofclaim 11, wherein the at least one valve is positioned external to thereserve tube.
 18. The shock absorber of claim 11, wherein the at leastone valve includes a first valve that is disposed in fluid communicationwith multiple passageways of the plurality of passageways.
 19. The shockabsorber of claim 11, wherein the at least one valve includes multiplevalves where there is one valve for each passageway in the plurality ofpassageways such that each passageway receives fluid from only onevalve.
 20. A shock absorber comprising: a pressure tube having an innersurface that defines a working chamber and an outer surface opposite theinner surface of the pressure tube; a piston assembly attached to apiston rod and slidably disposed within the pressure tube, the pistonassembly dividing the working chamber into an upper working chamber anda lower working chamber; a reserve tube disposed around the pressuretube, the reserve tube having an inner surface that faces the pressuretube and an outer surface opposite the inner surface of the reservetube; a rod guide assembly attached to at least one of the reserve tubeand the pressure tube, the piston rod extending through the rod guideassembly such that the rod guide assembly supports the piston rod; abaffle positioned radially between the pressure tube and the reservetube to define a baffle channel and a reservoir chamber between thepressure tube and the reserve tube; and at least one valve positionedwithin the rod guide assembly and disposed in fluid communication withthe upper working chamber and the baffle channel for controlling fluidflow between the upper working chambers and the baffle channel, whereinthe baffle channel includes a plurality of passageways that are definedby grooves in the baffle together with at least one of the outer surfaceof the pressure tube and the inner surface of the reserve tube, theplurality of passageways having a non-linear shape to provide a tortuousfluid flow path along the baffle, at least one of the plurality ofpassageways disposed in fluid communication with the at least one valveand the reservoir chamber.